1. Field of Invention
This invention relates to bicycles, specifically to a saddle positioning device. It relates particularly to a mechanism which allows simultaneous positional adjustment of a bicycle saddle forwardly and upwardly, and rearwardly and downwardly.
2. Discussion of Prior Art
All terrain bicyclists have special requirements for saddle positioning systems. The correct saddle position is the most important requirement, simplicity of operation, safety and durability also being important concerns.
When pedaling up a slope, the preferred saddle position is upward and forward. This allows extension of the bicyclists legs which permits maximum power output, and a shift of the riders weight forward for improved weight distribution. When riding down a slope or on very uneven terrain most bicyclists prefer a downward and rearward saddle position. The lower saddle height provides additional clearance between the saddle and the rider, while the rearward positioning increases stability the angle of the sliding mechanism is greater than 40 degrees from horizontal to ensure a significant change in saddle height (leg extension) when the saddle is moved to the rearward position.
Heretofore saddle position adjusting devices have addressed some, but not all, of the special requirements for all terrain bicycles. U.S. Pat. No. 4,772,069 to Szymski, 1988, describes a longitudinally adjustable saddle mounting. The invention does not address the need for simultaneous upward or downward adjustment. U.S. Pat. No. 4,919,378 to Iwasaki and Shogo, 1990, describes a support structure for a bicycle saddle which extends obliquely upwardly and forwardly. The invention allows correct positioning of the saddle but the design is not necessarily suited to rough all terrain bicycling use. Operating the adjustment lever requires removing one hand from the handlebar which is unsafe and undesirable. The cylindrical shape of the oblique sliding post has poor resistance to torsional loads imposed by lateral forces on the saddle. The indirect load path, from the saddle to the frame, also increases deflections and reduces strength.